Electric circuit for rapidly igniting a discharge tube

ABSTRACT

This invention discloses a circuit for rapidly and certainly igniting a discharge tube such as a fluorescent lamp, mercury-arc lamp, neon tube lamp or the like, which comprises a capacitor adapted to effect charge or discharge thereof at substantially the peak value of AC wave of power source by the action of a switching means, a transformer or ballast choke coil which is adapted to produce high voltage pulse in response to said charge or discharge of the capacitor, said high voltage pulse being applied to a discharge tube at its electrodes which are preliminarily heated thereby to ignite the discharge tube. According to this invention, simultaneously when a power source is closed, a high voltage is generated at substantially the peak value of positive and/or negative half cycle of the AC power source by the operation of a specific circuit, thereby enabling the discharge tube to be rapidly or instantaneously ignited. The present circuit is very useful for various commercial purposes.

0 United States Patent [1 1 3,676,734 Shimizu et al. 1 July 11, 1972 [541 ELECTRIC CIRCUIT FOR RAPIDLY 3,334,270 8/1967 Nuckolls .315/100 x IGNITING A DISCHARGE TUBE 3,466,500 9/1969 Peek ..3l5/l00 [72] Inventors: Tetsujl Shimlzu; Makoto Iwakura, both of Primary Examiner Roy Lake Nagoya Japan Assistant Examiner-Lawrence J. Dahl [73] Assignee: Kabushlkl Kalsha Tokai Rika Denkl Blanchard and Flynn Seisakusho, Nishikasugai-gun, Aichi prefecture, Japan ABSTRACT [22] Filed: Nov. 14, 1969 This invention discloses a circuit for rapidly and certainly igniting a discharge tube such as a fluorescent lamp, mercury- [211 APPI'NO: 876898 arc lamp, neon tube lamp or the like, which comprises a capacitor adapted to effect charge or discharge thereof at sub- 30 Foreign li i P i i D t stantially the peak value of AC wave of power source by the action of a switching means, a transformer or ballast choke NOV. 15, 1968 Japan ..43/83232 Co which is adapted to produce h voltage pulse in response to said charge or discharge of the capacitor, said high [52] U.S.Cl ..315/200,3l5/2l9,315/227, voltage pulse being applied to a discharge tube at s elec 5/7258 trodes which are preliminarily heated thereby to ignite the [51] 5 9 discharge tube. According to this invention, simultaneously Field of Search i 5 when a power source is closed, a high voltage is generated at substantially the peak value of positive and/or negative half cycle of the AC power source by the operation of a specific [56] Rem-megs Cited circuit, thereby enabling the discharge tube to be rapidly or in- UNITED STATES PATENTS stantaneously ignited. The present circuit is very useful for various commercial purposes. 2,410,198 10/l946 Buckley ..3l5/l00 X 3,259,797 7/1966 Heine et al ..315/ I00 X 17 Claims, 23 Drawing Figures 0 Ti 77 i /E F\ R11 R14 R15 R17 E c i D512 DZ] R Z DZ l2 F I R13 Tr Rl sum 113 0r 12 mmHI mm:

PATENTEDJuL 1 1 m2 V 3 6 76. 7 34 sum 07 0F 12 TIME TIME

TIME

VOLTAGE 0 CURRENT o VOLTAGE 0 Lu 5 2* E C F VOLTAGE 0 CURRENT VOLTAGE O Amen [KP PATENTEnJuL 1 1 1972 sum naur12 ig l u\ VOLTAGE 0 CURRENT O VOLTAGE o E u w E g VOLTAGE PATENTEBJIJLH I972 sum 12 or 12 ELECTRIC CIRCUIT FOR RAPIDLY IGNITING A DISCHARGE TUBE This invention relates to circuit for rapidly igniting ,a discharge tube.

conventionally there has been proposed various igniter circuits for a so-called rapid start type discharge tube or lamp such as fluorescent lamp, mercury-arc lamp, neon tube lamp or the like. In these conventional igniter circuits, however, there is generally used a leakage transformer having a secondary high voltage coil which is expensive. The use of such leakage transformer leads to such disadvantage that the apparatus employing a rapid start type discharge tube becomes,

as a whole, much expensive.

An object of the present invention is to provide a circuit for rapidly or instantaneously igniting a discharge tube, which employs no leakage transformer and is simple in structure, leading to the considerable reduction of cost.

Another object of the present invention is to provide an igniter circuit for a discharge tube, which is provided with a preheater unit, that is, another circuit for preliminarily heating the electrodes of a discharge tube thereby to enable the discharge tube to be ignited in substantially simultaneity with the closure of electric power source, consequently being capable of effecting the ignition more rapidly than the conven-. tional igniter circuit employing a leakage transformer.

Another object of the present invention is to provide an igniter circuit for a discharge tube, which repeatedly produces high voltage pulse of the same number with that of the frequency of power source until a discharge tube such as a fluorescent lamp or the like is ignited, thereby enabling the,

discharge tube to be discharged by the action of the subsequent high voltage pulse and consequently ignited even if the first discharge lamp fails to effect the ignition.

Another object of the present invention is to provide an igniter circuit for a discharge tube which, after the discharge tube has once been ignited, can continue to effect the ignition by the actionof a conventional stabilizer, independentlyof a high voltage pulse producing circuit.

Another object of the present inventionis to provide an igniter circuit which ignites a plurality of discharge tubesor lamps simultaneously.

Another object of the present invention is to provide an igniter circuit which ignites a plurality of discharge tubes with such certainty that even if one of said discharge tubes is in trouble the remaining discharge tubes can be ignited without any disorder.

Another object of the present invention is to provide an electric circuit for igniting discharge lamps which ensures the igniting operation; is made at low cost since a transformer for heating filaments is not used, and is compact and light in weight. 7

Another object of the present invention is to provide a discharge lamp igniting circuit in which a ballast choking coil and a secondary coil of a transformer are connected in series, and as a voltage to be applied to a discharge lamp, high voltage pulses generated on the ballast choking coil and the secondary coil of the transformer are used so that the resultant higher voltage can be applied to the discharge lamp, thereby rendering the ignition of the discharge lamp more certain.

Another object of the present invention is to provide a discharge lamp igniting circuit in which a diode is connected so as to generate high voltage pulse at every cycle of AC waveform, whereby larger electric current flows through a transformer when pulse is generated, thereby enabling the ignition of the discharge lamp to be more certain.

Another object of the present invention is to provide a discharge lamp igniting circuit in which a tertiary coil and a biquadratic coil for heating a filament are provided in a trans former so that a pulse voltage proportional to a pulse voltage of a primary coil is induced on the tertiary and biquadratic coils and an end-arc is generated at the electrode of a discharge lamp, thereby enabling the ignition of the discharge lamp to be more certain.

Another object of the present invention is to provide a discharge lamp igniting circuit in which a power required for preheating a filament is automatically reduced after the discharge lamp has once been ignited thereby rendering the life remarkably long, as compared with the conventional discharge lamps having a continually heating unit.

Another object of the present invention is to provide an electric circuit for sequentially igniting a fluorescent lamp most suitable to the advertisement etc. due to the fact that the fluorescent lamp is ignited simultaneously with the application of the power supply and also the fluorescent lamps can be sequentially turned on and are simultaneously turned off.

Another object of the present invention is to provide an electric circuit for igniting an AC load in which a diode is connected to a capacitor of time constant circuit to retain a holding current of SCR, and the capacitor discharges while the holding current is retained, so that the load can be kept as it is energized for a relativelyprolonged period of time, and this makes energization of load distinguish from deenergization thereof.

The essential feature of the present invention consists in a circuit for rapidly and certainly igniting a discharge tube or lamp such as a fluorescent lamp, mercury-arc lamp, neon tube lamp or the like, which comprises a capacitor adapted to effect charge or discharge thereof at substantially the peak of AC wave of power source by the action of a switching means, a transformer or ballast choke coil which is adapted to produce high voltage pulse in response to said charge or discharge of the capacitor, said high voltage pulse being applied to a discharge tube at its electrodes which are preliminarily heated thereby to ignite the discharge tube.

It should particularly be noted that various embodiments including changes, omissions, additions, substitutions and/or other modifications may be made without departing from the scope of the invention. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. I-A isa circuit diagram showing the principle of inducinga high voltage according to the present invention;

FIG. l-B is a circuit diagram showing an embodiment of the present invention;

FIG. 2 is a circuit diagram showing another embodiment of the present invention;

FIG. 3 is a circuit diagram showing another embodiment;

FIG. 4-A is a circuit diagram showing another embodiment of the present invention;

FIG. 4-8 is a circuit diagram showing another embodiment wherein the similar circuit to that of FIG. 4- A is used for igniting a plurality of discharge lamps;

FIG. 4-C 11,, b,, and c represent a series of waveforms useful in explaining the operations of the embodiments shown in FIGS. 4-A and 4-8, respectively;

FIG. S-A and FIG. 5-8 are circuit diagrams showing further embodiments of the present invention;

FIG. 5,-C and FIG. 5-D represent a series of waveforms useful in explaining the operations of the embodiments shown in FIG. 5-A and FIG. 5-8, respectively;

FIG. 5-H and FIG. S-F are circuit diagrams showing further embodiments of the present invention;

FIG. 5-G and FIG. S-I-I represent a series of waveforms useful in explaining the operations of the embodiments shown in FIG. S-E and FIG. 5-F, respectively;

FIG. 6-A and 6-B are circuit diagrams showing the principles of further embodiments of this invention;

FIG. 6-C, FlG. 6-D, FIG. 6-E and FIG 6-F are circuit diagrams of the embodiments realizing the principles shown in FIG. 6-A and FIG. 6-B;

FIG. 7 is a diagram of a circuit for sequentially igniting a fluorescent lamp, in which a discharge tube igniting circuit embodying this invention is employed; and

FIG. 8 is a diagram of a circuit for igniting an AC load, in which a discharge tube igniting circuit embodying this invention is employed.

Corresponding reference characters indicate corresponding parts throughout the figures of the drawings.

Referring now to FIG. l-A, characters E and S designate a DC power source and a switch connected thereto in parallel, respectively. Character F indicates a discharge tube or lamp, for example, fluorescent lamp. A ballast choke coil L is connected between the positive electrode of the DC power source E and the switch S. In such circuit, when the filament of the lamp F is preliminarily heated and then the switch S is opened, the choke coil L will immediately produce a high electric voltage, thereby enabling the lamp F to be ignited. This principle is realized in the present invention as follows: a silicon controlled rectifier element Ds is employed for the switch S, which performs the same operation as the switch S in interrupting the gate current.

Referring now to FIG. l-B, there is shown an embodiment of this invention. There is provided an ignition starting circuit for a discharge lamp such as fluorescent lamp, which comprises an initial stage SCR which is adapted to be turned on during a positive half cycle thereby to render a transistor conductive, a subsequent stage SCR adapted to be turned off by the interruption of the gate current, said initial stage SCR and said subsequent stage SCR being connected in parallel between the discharge lamp and AC power source, said interruption being caused by an inverse voltage which is applied between an anode and a cathode by the turn-on of said initial stage SCR, and a ballast choke coil adapted to apply a highvoltage counter electromotive force between the lamp and an electrode by the turnoff of said subsequent stage SCR and to effect a discharge, and connected in series between the lamp and the AC power source.

Characters E and T designate an AC power source and a transformer to pre-heat the filament of a discharge lamp F such as a fluorescent lamp, respectively. The primary side of said transformer is connected in parallel to said power source E, whereas the secondary side of said transformer is connected to the filament of the lamp F.

One terminal of the ballast choke L is connected to the primary side of the transformer T and the other terminal to the filament of the lamp F. To the junction point of the choke L and the filament of the lamp F, one terminal of each resistor R,,, R R, and R, is connected. To the other terminal of the resistor r,,, a resistor R of which the one terminal is connected to an electrode of the power source E, and a Zener diode D2,, are connected. To the other terminal of the resistor R the anode of the silicon controlled rectifier element D5,, (hereinafter referred to merely as SCR) and the capacitor C are connected. Furthermore, to the other terminal of the resistor R are connected the resistor R, one terminal of which is connected to an electrode of the power source E, the collector of a transistor Tr and a Zener diode D2 To the other terminal of the resistor R, are connected the anode of SCR (Ds,,) and the other terminal ofsaid capacitor C.

The cathode of said SCR (Ds,,) is connected to an electrode of the power source E, and the gate thereof is connected to the Zener diode (D211) and the resistor R one terminal of which is connected to an electrode of the power source and the base of the transistor Tr. The emitter of the transistor Tr is connected to an electrode of the power source E.

The cathode of another SCR D5,: is connected to one electrode of the power source E and the gate thereof, is connected to the resistor R one terminal of which is connected to one electrode of the power source E and to the Zener diode DZ In operation, the filament of the lamp F is preheated by the transformer T. Taking the voltages of the Zener diode D2,, and the Zener diode D2,, as VDZ and VDZ, respectively and setting VDZ,, VDZ, SCR (Ds is ignited, prior to D5,, during the positive half cycle at its portion corresponding to a small degree of angle. Since at this time SCR (Ds,,) remains turned ofl, the capacitor C is charged positively on the anode side of this SCR (Ds,,) and negatively on the anode side of SCR (Ds When the terminal voltage of the resistor R reaches the Zener voltage VDZ,, of the Zener diode D2,,, SCR (Ds,,) is ignited during the positive half cycle at its portion corresponding to a larger angle than the other SCR D5 and turned on. When this SCR (Ds,,) is rendered conductive, the terminal (the anode side of SCR (Ds,,)) of the capacitor C which has been charged positively is immediately connected to the cathode side of SCR (Ds,,). Between the anode and cathode of SCR (Ds is applied the inverse voltage of the capacitor C to turn off said SCR (Ds,,). However, evern when the inverse voltage of the capacitor C is applied to this SCR (Ds to turned off it, current flows to the gate during the whole range of the positive half cycle and said SCR (Ds,,) is immediately turned on after once being turned off, which is undesirable. For this reason, the transistor Tr is provided to interrupt the gate current of SCR (Ds immediately on SCR (Ds,,) being turned on. That is, simultaneously with the turnon of SCR (Ds,,) the Zener current of the Zener diode D2,, flows through the base of the transistor Tr, which renders the transistor conductive and makes the potential of the gate of SCR (Ds equivalent to that of the cathode potential thereby to interrupt the gate current.

Thus, on SCR (Ds turned off, the current defined by the resistor R which has being flowed through the ballast choke L, immediately stops to flow. Accordingly, on the ballast choke is generated a counter electromotive force, which is then applied to the terminals of the lamp F to induce discharge and begin normal discharge. At this instance, however, if the filament of the lamp F has been not heated sufficiently, discharge is not carried out. Yet, as the high voltage is continuously generated during the positive half cycle while discharge is not carried out, discharge consequently comes to start as the filament becomes heated.

Once discharge begins, the voltage of the terminals of the lamp F is reduced to a discharge maintaing voltage of several tens volts. Because the circuit is so designed that the gates of SCR (Ds,,) and (Ds,,) do not operate below the discharge maintaining voltage, said SCR (Ds,,) and (Ds remain turned off. Hence, this electronic circuit is brought into the condition separated from the lamp F. The ballast choke L merely operates to stabilize the lamp F.

As described, above, in this embodiment, at the same time a power source is closed, a high voltage is generated at substantially the peak of a positive half cycle of alternating current by the operation of an electronic circuit and the function of a ballast choke and if a lamp such as a fluorescent lamp has been preheated, discharge is carried out and the lamp is ignited as soon as a power source is closed. Accordingly, if this embodied circuit is utilized, for instance, for a flashing circuit of advertisement, the same function as that of an ordinary incandescent lamp can be obtained. After the lamp has been ignited, only the ballast choke operates as a stabilizer and the electronic circuit is not operated, thereby lengthening the life of said electronic circuit and achieving the intended object as well.

Referring now to FIG. 2 showing another embodiment of this invention, there is provided an electric circuit for producing pulse for igniting a fluorescent lamp comprising a ballast choke coil having a secondary coil; a capacitor; a thyristor and a neon tube lamp; said ballast choke coil and capacitor producing a high-voltage pulse at substantially the peak of positive half cycle of power source voltage in cooperation with said thyristor and neon tube therely to dischage the fluorescent lamp, and said fluorescent lamp being kept as it is ignited by said ballast choke coil only.

In FIG. 2, reference E is an AC power source; T is a transformer for preheating a fluorescent lamp which is connected in parallel to said AC power source E and has the secondary side, terminals of which are connected to filaments of fluorescent lamp FL. One terminal of said fluorescent lamp FL is connected to one terminal of power source E and the other terminal thereof is connected to the other terminal of power source E through the'primary coil L,, of ballast choke coil CH. One terminal of secondary coil L of said ballast choke coil Cl-[ is connected to the other terminal of power sourceE and the other terminal thereof is connected to one terminal of power sourcethrough a capacitor C, resistorll, and thyristor Ds in series connection. A diode D is connected to said thyristor Ds.

A resistor R a neontube lamp Ne, a diode D and a resistor R inseries connection with each other are connected in parallel to said fluorescent lamp. A gate of'thyristorDsis connected to a junction point of diode D with the resistor R The thus connected electric circuit operates as follows.

The filaments of fluorescentlampFL is preheated by .the transformer. When the voltage of negative half cycle is applied by the power source E, the voltage is charged to the capacitor C, so that said capacitor bears thepositive electrode at the side near to the resistorR and the negative electrode at.the side near to the secondary side of the ballast choke coil CH. The discharge current does not flow to the neon tube lamp Ne at the negative half cycle owingto the diode D connected thereto in the backward direction. Accordingly,- the neon tube lamp is not yet ignited. The thyristor Ds is left as it is turned off, since the inverse voltage is applied to the thyristor Ds.

Subsequently, when-the voltage of positive half cycleis applied to the capacitor and the voltage of said capacitoris raised to the voltage at which discharge of the neon tube lamp will start, the discharge current flows to said neon tube lamp, whereupon current flows to the gate of thyristor Ds to turn on said thyristor. Accordingly, the thyristor Ds is turned on at substantially the peak of positive half cycle, hence theappropriate oscillating voltage generates at bothterminals of secondary coil L with the aid of the secondary coil L of ballast choke CH, thecapacitor C and resistance of said secondary coil L Said pulse oscillating voltage is more raised by the primary coil L of ballast choke coil CH to produce thel-highvoltage pulse. Said Hl-llGH-voltagepulseis impressed-to the fluorescent lamp FL to excite the local discharge, and subsequently, normal discharge. Normally, the high-voltage pulse must-be synchronized with the power source where the normal discharging is kept on, but in the present embodiment, the thyristor Ds is caused to trigger by utilizing the neon tube lamp Ne of which the discharge starting voltage is comparatively hi h.

lhus, the normal discharge is started, and the voltage at both terminals of fluorescent lamp FL drops below the discharge starting voltage of neon tube lamp Ne, so that the neon tube lamp Ne does not discharge at the subsequentpositive half cycle and accordingly, current doesnot flow to the gate of thyristor Ds, hence said thyristor is kept as it is turned off. That is to say, the high-voltage pulse produced at the primary coil of ballast choke coil Cl-l causes the fluorescent lamp FL to trigger to be ignited, and thereafter, the trigger circuit is separated from the main circuit.

As set forth in the foregoing, in the electric circuit of this embodiment, if the filaments of fluorescent lamp is preheated, the capacitor is charged at the negative half cycle in the waveform while the neon tube lamp discharges at the positive half cycle to turn on the thyristor at substantially the peak of said positive half cycle; the pulse oscillating voltage is produced with the aid of .the secondary coil of ballast choke coil, said capacitor and resistance of said secondary coil; and the pulse voltage is further raised by the primary coil of choke coil, whereupon the fluorescent lamp starts discharging-Thus, the fluorescent lamp-discharges immediately when the power source is closed. Accordingly, it is advantageous that in using the electric circuit as an igniting circuit in an advertising device, the fluorescent lamp which has been never applicable can be ignited likely to an incandescent lamp. The electric circuit has other advantages that the durability is greatly improved, since only the ballast cheke is kept in operation as a stable unit after ignition of the lamp, while the trigger circuit becomes inoperative; and the circuit is manufactured at low cost and compact due to the simplicity in structure.

voltagepul'se at an oscillation producing coil; and neon tube lamps connected between a gate of said controlled rectifier element and each of ballast choke coils causing said con- .trolled rectifier element to turn on at substantially the peak of the positive half cycle; said ballast choke coils raising voltage of said high-voltage pulse to igniterespective discharge lamps.

Reference E is an AC power source; FL FL32 and FL are discharge lamps such as afluorescent lamp each of which has filaments-connected at one terminal of one electrode thereof to one terminal of power source E and connected at one terminal of the other electrode to the other electrode of power surce E through each of ballastchoke coils Cl-l CH and CH Reference T is a-transformer for preheating filaments F 1 F1 and F1 which has a primary coil T, connected to the power source E andsecondary coils. One of secondary coils T a is connected to one electrode of each of filaments 'FL FL;,.,. and FL and the other secondary coils T b, T 0,

and T d are connected-to each of the other terminals of said filaments.

L is a coil for generating oscillation one terminal of which is connected to one electrode of power source at the side con nected to the ballast choke coil CH and the other terminal of which is connected to the other electrode of power source B through a capacior C and thyristorDs in series connection. The oscillation producing coil L and ballast choke coil CH CH in combination constitute a transformer. A diode D is in the backward direction connected in parallel to the thyristor Ds. Between a gate of thyristor Ds and one electrode of the power surce E, a resistor R and diode D are connected. The diode D is disposed for protecting the thyristor Ds.

The resistorR and'neon tube lamp Ne the resistor R and neon tube lamp Ne and the resistor R and neon tube lamp Ne respectively. in series connection are connected to a junction point of ballast choke coils Cl-l CH with filaments of discharge lamps FL FL The other terminal of respective neon tube lamps Ne Ne or Ne is connected to the gate of thyristor DS.

The operation of the thus connected circuit is as follows. The discharge lamps FL, F L are preheated by the transformer for preheating T. When the negative half cycle of power source voltage is applied, the capacitor C is charged 30 through the diode D positively at the side near to the thyristor Ds and negatively at the side near to the oscillation producing coil L. The capacitor C does not discharge if charging to said capacitor C completes and the time of discharging comes, since the thyristor Ds is left as it is turned off and the diode D is connected in the backward direction. At this time, the neon tube lamps Ne Ne discharge at substantially the peak of the negative half cycle, but the thyristor D5 is kept as it is turned off since the positive current is not yet fed.

Subsequently, when the voltage of positive half cycle is applied and the voltage is raised to the voltage at which the neon tube lampsNe Ne start discharging, the discharging currentflows to said neon tube lamps Ne Ne so that current flows to the gate of thyristor Ds to turn on said thyristor. Accordingly, the thyristor D5 is turned on at substantially the peak of the positive half cycle, and an appropriate oscillation voltage is produced at both terminals of oscillation producing coil L with the aid of the capacitor C, ballast choke coils CH CH and resistance of said ballast choke coils CH CH By this time, charging to the capacitor C is effected through the side near to the thyristor Ds, hence a high-voltage pulse oscillation voltage is produced at the oscillation producing coil L by the discharging current of the capacitor which starts discharging at the same time when said thyristor Ds is turned on and the charging current flowing to the capacitor C through the positive side near to said oscillation producing coil L. Said pulse oscillating voltage is further raised by the ballast choke coils CH CH to produce a high-voltage pulse. Said high-voltage pulse is impressed on the discharge lamps FL;, F L to excite a local discharge, which is followed by the normal discharge. The high-voltage pulse must be synchronized with the power source voltage which maintains the discharge lamps in the normal discharging, and in this embodiment, the neon tube lamps Ne Ne of which the discharge starting voltage is comparatively high are utilized to make the thyristor Ds trigger.

As soon as the discharge lamps FL FL begin to effect the normal discharge, the voltage at both terminals of discharge lamps FL FL drops below the voltage at which the neon tube lamps Ne Ne will start discharging, hence the neon tube lamps Ne ,,,;,;,do not discharge at the subsequently the subsequent positive half cycle of power source voltage. Accordingly, current does not flow to the gate of thyristor Ds, so that the thyristor is left as it is turned off. In other words, the high-voltage pulse produced by the ballast choke coils CH CH causes the discharge lamps FL, F L;, to trigger, and thereafter, the trigger circuit is automatically separated from the main circuit.

Thus, all of discharge lamps FL FL are simultaneously ignited. In case one or more of plural discharge lamps fails to be ignited, any of neon tube lamps connected to the discharge lamp which remains not ignited is ignited at the subsequent positive half cycle. Consequently, the thyristor Ds is turned on by the circuit operation as set forth in the foregoing, and said discharge lamp is ignited with high-voltage pulse oscillating voltage.

ln the the electric circuit of this embodiment, the ballast choke coils CH CH and the oscillation producing coil L are combined into a unitary transfermer, and alternatively the oscillation producing coil may be connected to each of ballast choke coils. In this embodiment, three discharge lamps are connected, and the number of discharge lamps may be increased according to necessity, with increase in the number of neon tube lamps and ballast choke coils.

As described herein above, the electric circuit of this embodiment is so adapted that filaments of discharge lamps such as a fluorescent lamp are preheated; the capacitor is charged at the negative half cycle of power source through the diode; and the neon tube lamps discharge at the positive half cycle to turn on the semiconductor controlled rectifier element such as thyristor, so that the high-voltage pulse is produced at the oscillation producing coil, thereby igniting the discharge lamps through the ballast choke coils. The thus connected electric circuit has such advantages that its application is versatile, for example, it is useful as a flashing cirucuit for advertising purpose, since all discharge lamps are simultaneously ignited instantly when the power source is closed; the ignition operation is ensured since charging to the capacitor at the negative half cycle is effected through the diode, transfer of electric charge in said capacitor is increased which takes place synchronously when the semiconductor controlled rectifier element is turned on, hence the signal of high-boltage pulse is applied sufiiciently to ignite discharge lamps; the circuit is economical since ignition of a plurality of discharge lamps is effected by a single trigger pulse including a controlled rectifier element; and the durability of circuit is greatly prolonged, since the ballast choke coils serve as a stable element after the ignition of discharge lamps, while the trigger circuit becomes inoperative.

Referring now to FIGS. 4-A, 4-B and 4-C, there are illustrated further embodiments of this invention. There are shown: I

An electric circuit for igniting a discharge lamp which comprises an electric circuit for preheating filaments including a controlled rectifier element such as a thyristor adapted to turn on at substantially the peak of positive half cycle of a power source voltage and connected between filaments of said discharge lamp; and a high-voltage pulse generating circuit consisting of a capacitor and transformer connected in common to said controlled rectifier element; said filaments of discharge lamp being preheated through the controlled rectifier element adapted to turn on at substantially the peak of positive half cycle, said capacitor being charged at the negative half cycle of power source voltage and inversely rapidly charged at substantially the peak of the positive half cycle. whereupon said charging current produces an oscillating pulse at a primary side of transformer, said pulse is raised to excite a high-voltage oscillating pulse at a secondary side thereof, and the high-voltage oscillating pulse of the negative direction is impressed on said filaments, thereby igniting the discharge lamp; and

An electric circuit for igniting a plurality of discharge lamps which comprises a filament preheating circuit connected to filaments of a plurality of discharge lamps and adapted to preheat the respective filaments through said controlled rectifier circuit; and a high-voltage pulse generating circuit including a capacitor and transformer connected in common to said controlled rectifier circuit; said filament preheating electric circuit including a controlled rectifier element connected between respective filaments of discharge lamps and adapted to turn on at substantially the peak of positive half cycle of an AC power source and a gate current controlling circuit including neon lamps and connected to the respective filaments, said gate current controlling circuit feeding current to a gate of said controlled rectifier element to turn on said controlled rectifier element; said capacitor being charged at the negative half cycle of power source voltage and inversely rapidly charged at substantially the peak of the positive half cycle, whereupon said charging current produces an oscillating pulse at a primary side of transformer, and said pulse is raised to excite a high-voltage oscillating pulse at a secondary side thereof, and the high-voltage oscillating pulse of the negative direction is impressed on said filaments, thereby igniting said plurality of discharge lamps.

In FIG. 4-A, reference E is a or 200V. AC power source; CH is a ballast choke coil, one terminal of which is connected to said power source E; C is a capacitor for noise regulation which is connected to one polarity of power source E and the other terminal of said choke coil CH; FL is a discharge lamp such as a fluorescent lamp having filaments F and F each of which is connected at one terminal to the power source E. lf a discharge lamp of 32W or below is used, the discharge lamp is connected to the 100V power source, while if a discharge lamp of 40W and more is used, the discharge lamp is connected to the 200V power source E. T is a transformer having a secondary coil T one terminal of which is connected to a filament F of discharge lamp FL through a capacitor C and the other terminal of which is connected to the filament F of discharge lamp FL, and a primary coil T one terminal of which is connected to the power source E at the side near to choke coil and the other terminal of which is connected to a capacitor C The other terminal of capacitor C43 is connected to the anode of semiconductor controlled rectifier element Ds such as a thyristor through a diode D in the forward direction and to the filament F of discharge lamp FL through a diode D in the backward direction. The anode of controlled rectifier element 05 is connected to the filament F of discharge lamp FL through a diode D and the cathode thereof is connected to the filament F of discharge lamp FL. A gate of said SCR is connected to a connection point of a resistor R having one terminal connected to the filament F and a neon tube lamp Ne having one terminal connected to the filament F. of discharge lamp FL through resistors R. and R R is a resistor one terminal of which is connected to a connection point between the resistors R. and R, and the other terminal of which is connected to the filament F The electric circuit having such electric connection operates as follows.

If the power source E is closed, preheating current flows to the filaments F and F, of discharge lamp FL through the diode D only when the controlled rectifier element BS is turned on. When the positive half cycle of power source voltage is applied to said controlled rectifier element Ds and the voltage thereof is raised to the voltage at whichthe neon tube lamp Ne starts discharging, discharge current flows to said neon tube lamp Ne, so that current flows to the gate of rectifier element to turn on said rectifier element Ds. The neon tube lamp Ne used in this circuit is of the type which discharges at substantially the peak of positive half cycle, and therefore the controlled rectifier element Ds is turned on at substantially the peak of positive half cycle.

Now the explanation will be made on the case where the filaments F. and F of discharge lamp FL are sufficiently preheated with current determined by the choke coil CH, diode D and controlled rectifier element Ds. The capacitor C is charged negatively at the negative half cycle through the diode D and said negative voltage is retained until the controlled rectifier element Ds is turned on at substantially the peak of positive half cycle. This is shown in FIG. 4 C,a When the controlled rectifier element Ds is turned on, the capacitor C is rapidly charged to the substantially the peak of positive half cycle through the diode D so that the extremely large amplitude of discharging current flows to the primary side T of transformer T, thus the electromotive force generates as shown in FIG. 4 C,b,,. This produces a high-voltage oscillating pulse at the secondary side T of transformer T. Said high-voltage oscillating pulse has a phase which is inverted by 180 at a phase angle with respect to that of the high-voltage oscillating pulse generated at the primary side T thereof. Said high-voltage oscillating pulse voltage as seen in FIG. 4-C,c is impressed on filaments F and F of fluorescent lamp FL through the capacitor C The negative high-voltage pulse is impressed between filaments F and F, synchronously at substantially the peak of positive half cycle of the power source voltage. The filaments F and F are cut off in relation to pulse of the positive direction at the positive half cycle, but not cut off in relation to the negative pulse of the negative direction, hence the negative pulse is impressed on filaments R and F to excite a local discharge. Since the filaments F, and F are already preheated to a certain degree, the local discharge is accelrated to cause these filaments to normally discharge, thereby igniting the discharge lamp. Reference D is a diode for separating the preheating circuit from the high-voltage generating circuit.

When the discharge lamp FL is ignited, the voltage at both terminals of said discharge lamp FL drops to the discharge retaining voltage, so that the neon tube lamp Ne stops discharging, and therefore, the controlled rectifier element Ds is left as it is turned off. Accordingly, the operation of the preheating circuit and high-voltage generating circuit are caused to stop. Thus, the trigger circuit shown with the one-dotted line in FIG. 4-A becomes independent of the electric circuit including a discharge lamp.

The electric circuit as shown in FIG. 4-A is used either to ignite a discharge lamp FL of 6W, W, W, W or 32W with respect to the 100V power source, or to ignite a discharge lamp of more than W in relation to the 200V power source. In the meantime, in order to ignite a more than 40W discharge lamp using the lOOV power source, a leakage transformer is connected in parallel to the power source, so that the discharge lamp can be ignited in the same way as set forth in the foregoing example.

FIG. 4-8 shows an electric circuit for igniting a plurality of discharge lamp. In this example, two discharge lamps are connected. Said electric circuit of FIG. 43 comprises an additional electric circuit including a discharge lamp FL, a ballast choke coil CH, a capacitor for noise regulation C.,,', a capacitor C connected between a filament F of discharge lamp FL and secondary side T of transformer T, a diode D connected between a filament F.,, of discharge lamp FL and the anode of controlled rectifier circuit Ds, resistors R R and a neon tube lamp Ne, said another circuit being connected in parallel to said electric circuit of one lamp type as shown in FIG. 4-A. Diodes D and D are connected to prevent the gate circuits of neon tube lamps Ne, Ne from being interacted with each other.

The operation is as follows.

Likely to said electric circuit of one lamp type, the preheatingcurrent flows to the filaments F F and F F of the respective discharge lamps FL and FL through the controlled rectifier element Ds which is turned on by neon tube lamps Ne and Ne discharging at substantially the peak of positive half cycle, thereby preheating said filaments. With the charging current rapidly flowing to the capacitor C., an oscillating pulse voltage is produced at the primary coil which is proportional to a diferential value of charging current. Said pulse voltage is inverted to the secondary coil and raised to excite a high-voltage oscillating pulse of high frequency. Said highvoltage oscillating pulse is impressed on the discharge lamps FL and FL through the capacitors C and C thereby igniting the discharge lamps.

In the above embodiment, the discharge lamps FL and FL of 6, l0, I5, 20, 30 or 32W are connected to the V power source, and the more than 40W discharge lamps FL and FL are connected to the 200V power source. In order to connect more than 40W discharge lamps to the 100V power source. a leakage transformer is connected to each of discharge lamps FL and FL, so that said discharge lamps can be ignited.

The two-lamp type of electric circuit is exemplified, and needles to say, the number of discharge lamps may be increased according to application, with increase in the number of additional circuits connected thereto.

As set forth in the foregoing, the electric circuit of this embodiment is so adapted that the filaments of discharge lamp is preheated through a controlled rectifier element such as a thyristor, and a negative oscillating pulse is impressed on said filaments at substantially the peak of positive half cycle of the AC power source by the circuit consisting of the capacitor and transformer connected in common to said controlled rectifier element and providing a high voltage pulse, thereby igniting the discharge lamps. Hence, the electric circuit has such advantages that ignition of any type of discharge lamp, either a normal discharge lamp or a rapid-starting type of discharge lamp, can be positively and rapidly efi'ected; and, that if plural discharge lamps are connected to said circuit, the respective discharge lamps can be exactly ignited independently of other lamps, since these lamps are connected in parallel.

ReferringnowtoFIGS. S-A,5-B,5-C,5-D,5-E,5 -F, 5 G and 5 H, there are illustrated further embodiments of the present invention. These embodiments are:

a discharge lamp igniting circuit which is characterized in that a discharge lamp and a secondary coil of a transformer is connected in parallel to AC power source through the medium of a ballast choke coil, a circuit in which a primary coil of said transformer, a capacitor and a resistor are connected in series, is connected in parallel to AC power source, a switch which operates at substantially the peak of both positive and negative half cycles of a power source voltage is connected in relation to a circuit including said primary coil of the transformer, said capacitor and said resistor, said secondary coil producing a high voltage pulse, utilizing transient phenomena caused by charge and discharge of said capacitor which are caused by the operation of said switch, whereupon the thus produced high voltage pulse operates as a power source to produce a counter electromotive force on the ballast choke coil and then said high voltage pulse, counter electromotive force and power source voltage are applied to the discharge lamp: and

A discharge lamp igniting circuit which is characterized in that a discharge lamp and a secondary coil of a transformer are connected in parallel to AC power source through the medium of a ballast choke coil, a circuit in which a primary coil of said transformer, a capacitor and a diode for making approximately twice a charging or discharging current of said capacitor and applying it every cycle of AC voltage are connected is connected in parallel to AC power source, a switch which operates at substantially the peak of either positive or negative half cycle of power source voltage is connected in relation to a circuit including said primary coil of the transformer, capacitor and diode, said secondary coil producing a high voltage pulse, utilizing transient phenomena caused every cycle by charge and discharge of said condenser which are caused by the operation of said switch whereupon the thus produced high voltage pulse operates as a power source to produce a counter electromotive force on the ballast choke coil and then said high voltage pulse, counter electromotive force and power source voltage are applied to the discharge lamp.

In FIG. A, character E is a power source, T is a transformer, the primary coil T of which is connected in parallel to the power source E through the medium of a capacitor C and a resistor R, and the secondary coil T of which is connected in parallel to the power source E through the medium of a ballast choking coil CH. Reference character FL is a discharge lamp, such as a fluorescent lamp of which the filaments are connected at their ends to the secondary coil T of the transformer T. S is a switch connected in parallel to said resistor R and adapted to be closed at substantially the peak of both positive and negative half cycles in AC wave form. The filament (not shown) of said discharge lamp FL is connected to a filament heating transformer. With reference to FIG. 5 C, explanation will be made on a transient phenomena caused by the charge of the circuit which includes the capacitor C, the primary coil T of the transformer T, the resistor R and the switch S synchronizing with substantially the peak of either positive or negative half cycle in AC waveform. The charging voltage of the capacitor varies, as shown in the curve 0, depending on a time constant of the resistor R. If the switch 5 is closed at the time period t of substantially the peak of the positive half cycle in AC waveform, the resistor R is short-circuited by the switch S. Accordingly, the capacitor C is soon charged rapidly as shown in the curve a, hence the electric charge of the capacitor C shifts rapidly and an extermely large current curve b flows through the capacitor C. Since the current flows through the inductance of the primary coil T of the transformer T, counter electromotive force is generated on the primary coil T in pulses. The counter electromotive force generated on the primary coil T is boosted and induced thereby to be of high voltage pulse, which is applied to the discharge lamp FL. The high voltage pulse generated on the secondary coil T is applied to the closed loop looking toward left from the ends of the secondary coil T and consisting of the ballast choke coil, the capacitor C, the primary coil T the resistor R or the switch S, and as a result, a transient current flows,so that counter electromotive force is generated by the inductance ofthe ballast choke coil CH, and then applied to the discharge lamp FL. Thus, the high voltage pulse is generated on the secondary coil T of the transformer and on the ballast choke coil CH, and the thus generated high voltage pulses are added to AC waveform to produce the voltage as shown in the curve c, which is then applied to the discharge lamp FL thereby to facilitate the ignition. The above explanation was made for the case the switch S is closed at substantially the peak value of the positive half cycle. Yet, in case the switch S is closed at substantially the peak of the negative half cycle or in case the positions of the capacitor C and the switch S are interchanged, also, high voltage pulse is generated.

Referring now to FIG. 5 B, the switch S is, in the abovementioned circuit of the transformer T through the medium of the capacitor C connected in parallel with the primary coil T With reference to FIG. 5 D, the explanation will be made on the circuit being charged to the condenser C by the time constant of the resistor R. If the switch S is closed at the time period t of substantially the peak of the positive half cycle in AC waveform, the electric charge which has been charged to the capacitor C begins to be discharged rapidly as shown in the curve a, through the primary coil T of the transformer T. Accordingly, the electric charge of the capacitor C shifts very rapidly and an extremely large current (the current b) flows through the capacitor C. Since the current flows through the inductance of the primary coil T of the transformer, counter electromotive force is generated on said primary coil T in pulses. The counter electromotive force generated on the primary coil T, is boosted and induced. The subsequent operation is the same as that of the circuit of FIG. 5 A. Consequently, such induced high voltage pulses and the peak of AC waveform shown in the curve c is applied to the discharge lamp FL. In this case, the closed loop as seen toward left from the ends of the secondary coil T is fonned of the ballast choke coil CH, the switch S, and the resistor R. This embodiment is concerned with the case the switch S is closed at substantially the peak of the positive half cycle in the AC waveform. Yet, even when the switch S is closed at substantially the peak of the negative half cycle, high voltage pulse is generated.

In the circuit of FIG. 5 E, the diode D is connected in place of the resistor R in the circuit of FIG. 5 A. The anode side of the diode D and the cathode side thereof are connected to the power source E and to the primary coil T of the transformer T, respectively. The operation will be explained hereinbelow with reference to FIG. 5 G. If the voltage of the negative half cycle of AC waveform from the power source E is applied to the circuit, the capacitor C is charged positively on the side of the primary coil T of the transformer T and negatively on the side of the ballast choke coil CH through the diode D. The capacitor C does not start to discharge, even when the charge has been completed and the time for discharge has come. This is so because the switch is kept open and the diode D is connected inversely. Then, when the voltage of the positive half cycle is applied and the switch S is closed at the time period t of substantially the peak in the curve a, the charging current of the capacitor C which has been charged as shown in the curve b and the charging current to be charged negatively on the side of the ballast choke coil CH flow through the inductance of the primary coil T of the transformer T, resulting in counter electromotive force being generated on the primary coil T in pulses. Comparing this circuit with the abovedescribed circuit of FIG. 5 A, in the latter circuit, on closing the switch S either charging or discharging current from the capacitor C flows through the primary coil T during positive or negative half cycle of AC waveform, whereas in the circuit of FIG. 5 G, both charging and discharging currents flow simultaneously. Accordingly, the high voltage pulse boosted and induced on the secondary coil T is twice or thrice as high as that of FIG. 5 A. This high voltage pulse is added to the AC waveform as shown in the curve c and then applied to the discharge lamp FL. This embodiment is carried out by connecting the anode side of the diode D to the side of the power source E. The same result is also obtained by connecting the cathode side to the side of the power source E and by designing so that the switch S is closed at substantially the peak of the negative half cycle.

Referring to the circiit of FIG. 5 F, the capacitor C and the diode D which are connected in series are connected in parallel to the power source E and furthermore the switch S and the primary coil T of the transformer T are connected in parallel to said diode D through the medium of the diode D and the capacitor C, respectively. In the circuit, on the other hand, the secondary coil T of the transformer T is connected in parallel to the power source E through the medium of the ballast choke coil CH. The explanation of the operation will be made with reference to FIG. 5 H. When the voltage of the positive half cycle of the AC waveform from the power source E is applied to the circuit, the capacitor C is charged positively on the side of said diode D through the diode D When the ,voltage of the negative half cycle is then applied, the electric charge which has been charged to the capacitor C and the AC voltage are simultaneously charged to the capacitor C, so that the voltage up to about twice the voltage charged to the capacitor C is charged by the time period I. When the switch S is closed at the time period t, the discharging current of the capacitor C flows through the inductance of the primary coil T51 of the transfor mer T as shown in the curve 17,56 that counter electromotive force generated on said primary coil T is brought to have high voltage pulse about twice the one in the circuit of FIG. 5 B. Then high voltage pulse as same as that ofthe circuit of FIG. 5 F is obtained even if said diodes D and D are designed to be connected inversely and the switch S closed at substantially the peak of the positive half cycle.

It is to be noted that, according to this embodiment, charge and discharge is controlled by a switch which operates at substantially the peaks of both positive and negative half cycles in AC waveform of a power source voltage, high voltage pulse is induced by applying a charging or discharging current to a transformer and the thus induced voltage of a secondary coil of the transformer is further boosted by counter electromotive force caused by the inductance of a ballast choking coil, that the voltage adding high voltage pulse to a power source voltage is applied to a discharge lamp thereby to enable the igni- -tion of said discharge lamp to be effected with certainty and rapidity. Moreover, it is to be noted that a diode is connected in the circuit and charge and discharge of a capacitor are carried out every cycle so that the charging and discharging currents which flow through the transformer becomes further larger, thereby enabling not only the ignition of the discharge lamp to be more certain but also the intended objects to be achieved as well.

Referring to FIGS. 6-A, 6-B, 6-C, 6-D, 6-E and 6-F, there are shown further embodiments, the essential feature of which consists in a discharge lampigniting electric circuit wherein said electric circuit comprises a discharge lamp and a transformer connected in parallel to an AC power source through a ballast choke coil, primary coil of said transformer, a capacitor, a resistor or diode, and a switch adapted to synchronize with substantially the peak of AC, which comprises tertiary and biquadratic coils of said transformer for preheating filaments of discharge lamp which are combined into a unitary coil; a secondary coil producing a high-voltage pulse, utilizing a transient phenomena caused by charging and discharging of a capacitor, whereupon the thus produced high-voltage pulse produces a counter electromotive forceat the ballasbchoke coil; and said tertiary and biquadratic coil producing a pulse voltage proportional to that of the primary coil.

In FIG. 6-A showing a theoretical circuit, E is a power source, T is a transformer, the primary coil T of which is connected in parallel to the power source E through the medium of a capacitor C and a resistor R, and the secondary coil T of which is also connected in parallel to the power source E through a ballast choke coil CH, FL is a discharge lamp, such as fluorescent lamp, which has filaments connected at one terminal to the secondary coil T of the transformer T, and S is a switch which is connected in parallel to said resistor R, and closed at substantially the peak of either positive or negative half cycle in AC waveform. The filaments of the said discharge lamp FL are connected to the heating transformer T connected in parallel to the power source E. Describing the transient phenomena caused by the charging to this circuit, the capacitor is charged with the voltage determined by the time constant of the resistor R. The discharge lamp FL is to be preheated by the filament heating transformer T. If the switch S is now closed at substantially the peak of the positive half cycle in AC waveform, the resistor R is short-circuited by the switch, and therefore the capacitor is rapidly inversely charged,'resulting in the immediate transfer of the electric charge of the capacitor C and extremely large flow of the current through the capacitor. Since the current flows through the inductance of the primary coil T of the transformer T, counter electromotive force by this current is generated in a pulse form on the primary coil T The counter electromotive force generated on the primary coil T is boosted and induced by the secondary coil T which becomes of high voltage pulse and applied to the discharge lamp FL. At this time, the high voltage pulse generated on the secondary coil T is applied to the closed loop as seen toward the left from the ends of the secondary coil T consisting of the ballast choke coil CH, the capacitor C, the primary coil T and the resistor R or the switch S, so that the transient current flows therethrough and the counter electromotive force is generated by the inductance of the ballast choking coil CH and is further applied to the discharge lamp FL. Then, the high voltage pulse is generated on the secondary coil T of the transfonner T and theballast choke coil CH, and superposed to AC waveform to be applied to the discharge lamp FL, facilitating ignition of lamps. The above description is'concemed to the case where the switch is closed at substantially the peak of the positive half cycle, but if the switch is closed at substantially the peak of the negative half cycle, the high voltage pulse is generated with the positions of the capacitor C and the switch S exchanged. I

As illustrated in the theoretical circuit of FIG. 6-B, the switch S in the above-mentioned circuit of FIG. 6-A is now connected in parallel to the primary coil T of the transformer through the medium of the capacitor C. Describing the circuit in which the capacitor C is being charged by the time constant of the resistor R, when the switch S is closed at substantially the peak of the positive half cycle, the electric charge of the capacitor C which has been charged begins to be discharged rapidly through the primary coil T of the transformer T and the electric charge of the capacitor C transfers immediately, so that extremely large current flows through the capacitor C. Since this current flows through the inductance of the primary coil T of the transformer T, the counter electromotive force generated on the primary coil T is boosted and induced by the secondary coil T The succeeding operation is the same as in the circuit of FIG. 6-A, and the high voltage pulse is superposed on the peak of the AC waveform and applied to the discharge lamp FL. At this time, the closed loop, as seen toward the leftfromthe ends of the secondary coil T consists of the ballast choke coil CH, the switch S and the resistor R. The embodiment described above is concerned to the case the switch is closed at substantially the peak of the positive half cycle in AC waveform, but in the case the switch is closed at substantially the peak of the negative half cycle, the high voltage pulse is also generated.

Referring to the circuit of FIG. 6-C, the which the tertiary and biquadratic coils for filament heating are combined into a unitary form on the transformer T as shown in FIG. 6-A.

Describing the transient phenomena caused by the charging to the capacitor C, when the power source E is put on and the switch S is closed at substantially the peak value of either positive or negative half cycle, the alternating current on which the high voltage pulse is superposed is applied to the discharge lamp FL. At this time, the voltage applied to the secondary coil T of the transformer T is the value which is obtained by the impedance drop of the ballast choke coil CH from the power source voltage, and generally, when the impedance of the ballast choke coil CH is relatively low, most voltage is applied to the secondary coil T Accordingly the transformer T is excited by the secondary coil T so that the voltage directly proportional to the voltage applied tothe secondary coil T which is a primary coil forthetertiary and biquadratic coils is induced on the tertiary coil T and the biquadratic coil T and heats the filament of the discharge lamp. After the power source E is closed, when the filament is heated and electrons required for the discharge of the discharge lamp FL is emitted from the cathode, as described above, the voltage on which the high voltage pulse is superposed is applied to the discharge lamp FL, so that the normal discharge immediately begins. At the same time, in the alternating current induced on the tertiary and biquadratic coils T and T the pulse voltage proportional to the pulse voltage of the primary coil T is induced, by which so called end-arc is generated at the electrode of the filament, facilitating ignition of the discharge lamp furthermore.

On the other hand once the discharge lamp FL is ignited, the voltage at the tube end of the discharge lamp FL is 

1. A circuit for rapidly and certainly igniting a discharge lamp, comprising in combination: a power source having a fluctuating output voltage amplitude, means energizable from said source for preliminarily heating the electrodes of said discharge lamp, a capacitor, switching means actuable for rapidly changing the charge condition of said capacitor and including a switch, means for connecting said capacitor to said switching means, actuating means connected to said power source and switching means responsive to the phase of said power source for actuating said switching means at substantially the peak value of said output voltage of said power source, inductor means for producing a high voltage pulse in response to said change of said charge condition of said capacitor, means for connecting said inductor means to said capacitor and said switching means, and means applying said high voltage pulse to said discharge lamp at said electrodes.
 2. An ignition starting circuit for a discharge lamp, comprising in combination: an A.C. power source, a transistor having a control electrode, an initial stage SCR having a gate, means connecting the gate of said initial SCR with said power source for turning on said initial SCR during a positive half cycle of said source, means interconnecting the gate of said initial SCR and the control electrode of said transistor for rendering said transistor conductive upon conduction of said initial SCR, a subsequent stage SCR having a gate, means connected to the gate of said subsequent SCR for turning on said subsequent SCR prior to conduction of said initial SCR, and means connecting said transistor to the gate of said subsequent SCR for interrupting gate current thereof on conduction of said transistor to prevent further conduction of said subsequent SCR, said initial stage SCR and said subsequent stage SCR having further electrodes and at said further electrodes being connected in parallel and with the same polarity across each of the discharge lamp and A.C. power source, a ballast choke coil and means connecting same in series with said source and lamp and to said subsequent SCR for applying a high-voltage counter electromotive force to said lamp in response to the turn-off of said subsequent stage SCR so as to effect a discharge through said lamp, said subsequent SCR flowing current through said coil from said source when turned on.
 3. An electric circuit for producing a pulse for igniting a fluorescent lamp, comprising in combination: an A.C. power source, a ballast choke coil in circuit with said lamp and source, a thyristor and a neon tube lamp and means connecting said neon tube lamp to the gate of said thyristor and to said A.C. source for enabling said thyristor for conduction substantially at a voltage peak of said A.C. supply, a further coil, a capacitor and means connecting said further coil and capacitor in series with said thyristor across said source for producing a pulse in said further coil substantially at said peak in response to discharge of said capacitor through said thyristor and source and further coil, and means inductively coupling said further coil to said lamp for substantially simultaneously applying a high voltage to said lamp to initiate discharge of said lamp, said fluorescent lamp being kept ignited by current flow thereto from said source through said ballast choke coil.
 4. An electric circuit for igniting a plurality of discharge lamps, comprising in combination: a plurality of ballast choke coils, a power source, means connecting said plurality of discharge lamps in parallel to said power source through respective ones of said ballast choke coils, a diode and a capacitor and means connecting said diode and capacitor in series with said source for charging said capacitor during a negative half cycle of power source voltage through said diode, a semiconductor controlled rectifier element, an oscillation producing coil and means connecting said controlled rectifier element and oscillation coil to said capacitor for causing said capacitor to discharge as well as be inversely charged by said controlled rectifier element when said controlled rectifier element is turned on, thereby producing a high-voltage pulse in said oscillation producing coil usable for igniting said plurality of discharge lamps, and a plurality of neon tube lamps and means connecting each said neon tube lamp between a gate of said controlled rectifier element and a respective one of said ballast choke coils for causing said controlled rectifier element to turn on at substantially the peak of the positive half cycle of said power source.
 5. An electric circuit for igniting a discharge lamp, comprising in combination: a power source; means for preheating the filaments of said discharge lamp including a controlled rectifier element adapted to turn on at substantially the peak of positive half cycle of the power source voltage and connected between filaments of said discharge lamp; and a high-voltage pulse generating circuit comprising a capacitor and means connecting said capacitor to said source for charging said capacitor at the negative half cycle of power source voltage, a transformer, means connecting the secondary side of said transformer to said lamp, and means connecting said capacitor and the primary side of said transformer to said controlled rectifier element for rapidly inversely charging said capacitor at substantially the peak of the positive half cycle of said power source in a manner that said charging current produces an oscillating pulse at the primary side of said transformer, said pulse is raised to excite a high-voltage oscillating pulse at the secondary side thereof, and said high-voltage oscillating pulse is impressed on said filaments to ignite said discharge lamp.
 6. An electric circuit for igniting a plurality of discharge lamps, comprising in combination: an A.C. power source; a controlled rectifier circuit including a controlled rectifier element; a filament preheating circuit including means connecting said controlled rectifier element in circuit with the filaments of said discharge lamps and said source for preheating the respective filaments by conduction through said controlled rectifier element; a high-voltage pulse generating circuit including a capacitor, means connecting said capacitor to said source for charging said capacitor during the negative half cycle of said source voltage, a transformer, meAns connecting the secondary side of said transformer to said lamps, and means connecting the primary side of said transformer and said capacitor in common to said controlled rectifier circuit and responsive to conduction of said controlled rectifier element for rapidly inversely charging said capacitor at substantially the peak of the positive half cycle of said source voltage in a manner that the capacitor inverse charging current produces an oscillating pulse at the primary side of said transformer, said pulse is raised in voltage to provide a high-voltage oscillating pulse at the secondary side of said transformer and the high-voltage oscillating pulse is impressed on said filaments to ignite said plurality of discharge lamps and a gate current controlling circuit including neon lamps and means connecting said neon lamps to the filaments of respective ones of said discharge lamps, said gate current controlling circuit feeding current to a gate of said controlled rectifier element to turn on said controlled rectifier element at substantially the peak of the positive half cycle of said source.
 7. A discharge lamp igniting circuit, comprising in combination: an A.C. power source, a discharge lamp, a transformer having a secondary coil and a primary coil, means connecting said secondary coil across said lamp, a ballast choking coil, means connecting said secondary coil across said A.C. power source through said ballast choking coil, a capacitor, a resistor, means connecting said primary coil of said transformer and said capacitor and said resistor in a series circuit across said A.C. power source, a switch operable at substantially the peak of both positive and negative half cycles of the power source voltage and means connecting said switch across a portion of said series circuit for causing said secondary coil to produce a high voltage pulse utilizing transient phenomena caused by charge and discharge of said capacitor upon operation of said switch, whereupon the thus produced high voltage pulse produces a counter electromotive force on the ballast choke coil and then said high-voltage pulse, counter electromotive force and power source voltage are applied to the discharge lamp.
 8. A discharge lamp igniting circuit, comprising in combination: an A.C. power source, a discharge lamp, a transformer having a secondary coil and a primary coil, means connecting said secondary coil across said lamp, a ballast choke coil, means connecting said secondary coil in parallel to said A.C. power source through said ballast choke coil, a series circuit connected across said A.C. power source and including said primary coil of said transformer as well as a capacitor and a diode for making approximately twice charging or discharging current of said capacitor and applying it every cycle of A.C. voltage, a switch which operates at substantially the peak of the positive or negative half cycles of the power source voltage and means connecting said switch across a portion of said series circuit for causing said secondary coil to produce a high voltage pulse utilizing transient phenomena caused every cycle by charging and discharging of said capacitor whereupon the thus produced high voltage pulse produces a counter electromotive force on the ballast choke coil and then said high voltage pulse, counter electromotive force and power source voltage are applied to the discharge lamp.
 9. A discharge lamp igniting electric circuit, comprising in combination: an A.C. power source, a ballast choke coil, a discharge lamp and a transformer having a secondary coil connected in parallel to said A.C. power source through said ballast choke coil, a series circuit connected across said A.C. source and comprising a primary coil of said transformer as well as a capacitor and a current flow control device of a type capable of continuously passing D.C. current in at least one direction, a switch connected across a portion of said series circuit and adapted to synchronize with substantiAlly the peak voltage of said A.C. source, tertiary and biquadratic coils and means inductively energizing same from said A.C. source for preheating filaments of said discharge lamp, said tertiary and biquadratic coils being combined into a unitary coil, the secondary coil being inductively coupled at least to said primary coil for producing a high-voltage pulse utilizing a transient phenomena caused by charging and discharging of said capacitor, whereupon the thus produced high-voltage pulse produces a counter-electromotive force at the ballast choke coil, said tertiary and biquadratic coil producing a pulse voltage proportional to that of the primary coil.
 10. A circuit for sequentially igniting a plurality of fluorescent lamps, comprising in combination: a power source; lamp circuits each including a ballast choke coil connected between said source and a corresponding lamp, said ballast choke coil having a secondary coil, a capacitor chargeable from said source, a thyristor, a neon tube, means connecting said neon tube to said source and thyristor for turning said thyristor on at substantially the peak of the power source voltage, and means connecting said capacitor to said secondary coil and thyristor for causing discharge of said capacitor therethrough to produce a high voltage pulse in the ballast choke coil for igniting the corresponding one of said lamps, said lamp circuits being interconnected; a plurality of transistors and means connecting each said transistor to a corresponding one of said lamp circuits for rendering each said lamp circuit inoperative when the corresponding one of said transistors is rendered conductive; and control circuit means for controlling the conductive state of said transistors and connected to said transistors, said control circuit means including a transistor circuit for each said transistor, each said transistor circuit having two further transistors connected to a time constant circuit, and further including means interconnecting said transistor circuits for igniting said fluorescent lamps sequentially and for extinguishing said fluorescent lamps all at once after being ignited.
 11. An electric circuit for flashing an A.C. load, comprising in combination: an A.C. power source; a rectifier circuit having an A.C. side and a D.C. side, said A.C. side being connected to said A.C. power source through said A.C. load; a time constant circuit connected across the D.C. side of said rectifier circuit and including a resistor and capacitor; an SCR connected across said D.C. side of said rectifier circuit; means including a Zener diode connecting said capacitor to a gate of said SCR for turning on said SCR with current flowing to said gate thereof when the charging voltage of said capacitor of said time constant circuit is raised to exceed the Zener voltage of said Zener diode thereby to cause said capacitor of said time constant circuit to discharge; a diode and means connecting said diode from a point between said capacitor and Zener to a point between said SCR and said rectifier circuit for maintaining conduction of said SCR for a predetermined period of time thereby to energize the load.
 12. The circuit of claim 3 in which said further coil is inductively coupled to said ballast coil so that said pulse in said further coil induces a high voltage pulse in said ballast coil, said ballast coil applying said further high voltage pulse to said fluorescent lamp for discharging same substantially at said peak of said source.
 13. The circuit of claim 3 including a still further coil and means connecting same in series with said fluorescent lamp, said still further coil being inductively coupled to said further coil for discharging said fluorescent lamp upon appearance of said pulse.
 14. The circuit of claim 3 including a diode in series with said thyristor and means connecting said source, said ballast choke coil, said diode and thyristor in seriEs loop with the electrodes of said fluorescent lamp for preheating said electrodes when said thyristor conducts.
 15. The circuit of claim 4 in which said oscillation coil is inductively coupled to each of said ballast coils so that said high voltage pulse in said oscillation coil produces higher voltage pulses in each of said ballast coils, said ballast coils applying said higher voltage pulses to respective ones of said discharge lamps for igniting same.
 16. The circuit of claim 4 including a further coil inductively coupled with said oscillation coil, and means connecting said further coil in series with each of said discharge lamps for igniting said discharge lamps upon appearance of said high voltage pulse.
 17. The circuit of claim 4 including means for connecting each of said neon tube lamps in parallel with the corresponding one of said discharge lamps for causing ignition of said discharge lamps to prevent further actuation of said controlled rectifier element by the corresponding ones of said neon tube lamps and upon failure of one of said discharge lamps to ignite allowing the corresponding one of said neon tube lamps to subsequently turn on said controlled rectifier element. 